1. Field of the Invention
The present invention relates generally to the field of cleaning devices, and more particularly but not by way of limitation, to a device which utilizes a high pressure stream of liquid solvent to clean electrically conducting closures and the like with minimum exposure to the surrounding atmosphere.
2. Discussion
Much electronic apparatus can be adversely affected by the presence of externally generated electromagnetic radiation. In addition, some electronic apparatus will itself generate undesirable electromagnetic radiation. This phenomenon is generally termed Electromagnetic Interference (EMI) or alternately, Radio Frequency Interference (RFI). EMI is a recently used term which includes the entire electromagnetic spectrum, whereas RFI is more restricted to the radio frequency band, generally considered to be between the limits 10 kHz to 10 GHz. EMI is defined as undesired conducted or radiated electrical disturbances, including transients, which can interfere with the operation of electrical or electronic equipment. Such disturbances can occur anywhere in the electromagnetic spectrum.
For a variety of reasons it becomes necessary during operation, testing, and adjusting of the electronic apparatus to provide shielding to prevent the unwanted incursion of externally generated radiation or the escape of radiation being emitted by the electronic apparatus. The electromagnetic disturbance can also be transmitted by conductance.
Since the electronic apparatus to be shielded is frequently installed in other, larger equipment such as aircraft, automotive vehicles and the like, the shielding can take the form of a large, totally enclosed room having numerous openings, such as doors for passage of personnel and equipment, air vents, and access panels for various utility services. For completely effective EMI shielding, each opening must be so designed that full electrical continuity is firmly established completely around its periphery when the opening is closed.
One method of achieving this electrical continuity is to provide a tongue of electrically conductive material around the perimeter of the door, the tongue extending perpendicularly into the plane of the opening in such a manner so that when the door is closed, the tongue will penetrate into a matching slot in the wall surrounding the opening. The recessed cavity of the slot is fitted with a plurality of flexible, electrically conductive springs, usually beryllium copper, phosphor bronze, or the like. Thus, when the door is closed, electrical continuity is achieved and EMI shielding is complete.
Very large shielded rooms, as required to accommodate aircraft and the like, require openings so large that hinged doors are impractical; in these cases, sliding or roll-up type closures are used. In order to achieve the same degree of EMI shielding afforded by the tongue and slot method used on hinged doors, the inside surface of the door jamb is equipped with an electrically conducting metal plate on which are mounted a plurality of rows of flexible, electrically conducting springs. An inflatable bladder is installed behind the metal plate; when the door is closed, the bladder is inflated and the flexible, electrically conducting springs are pushed into contact with an electrically conducting strip, usually made of brass or the like, on the outer periphery of the door, thus achieving full electrical continuity and the required EMI shielding.
Over a period of time, dust and dirt can accumulate in the slot, and the conductive springs can become oxidized or otherwise corroded, resulting in a loss of electrical continuity and a diminution of EMI shielding. To insure the integrity of the shielding system, it is necessary to meticulously clean all of the slots surrounding the openings and the electrically conducting springs on a regular periodic basis. Heretofore, this cleaning has required much manual labor, involving hand scrubbing of the springs in the slot with a solvent soaked cloth wrapped around a spatula such as a putty knife. The electrically conducting springs, both in the recessed cavity and on the bladder plate, are rather fragile and highly susceptible to damage and permanent deformation during this hand cleaning process. It is to eliminate this manual cleaning that the present invention is directed.